PYGAME; Trying to activate sprite animation with a key

Question

Okay, so I managed to animate a sprite, but now I'm trying to activate it with a key and not just letting it be animated. What I want is it to be animated AFTER pressing a key and not without pressing any key.

Here is some code that seems to be causing it, I removed a bit of useless code (I hope it's useless). Also, sorry if it's a lot, but I couldn't check it, I'm in a rush to finish other stuff :(.

FULL CODE: pastebin.com/tXwDrua5

def load_image(name):
    image = pygame.image.load(name)
    return image

class SendSprite(pygame.sprite.Sprite):
    def __init__(self):
        super(SendSprite, self).__init__()
        self.images = []

        x = 0
        while x <= 56:
            self.images.append(pygame.transform.scale(load_image('send' + str(x) + '.png'), (SYNSCALE, SYNSCALE)))
            x += 1

        y = 57
        while y <= 69:
            self.images.append(pygame.transform.scale(load_image('send' + str(y) + '.png'), (SYNSCALE, SYNSCALE)))
            y += 1

        self.index = 0
        self.image = self.images[self.index]
        self.rect = pygame.Rect(SYNDIST, 0, 350, 350)

    def update(self):
        '''This method iterates through the elements inside self.images and 
        displays the next one each tick. For a slower animation, you may want to 
        consider using a timer of some sort so it updates slower.'''
        self.index += 1
        if self.index >= len(self.images):
            self.index = 0
        self.image = self.images[self.index]

def main():
    global gameIcon, FPSCLOCK, DISPLAYSURF, BASICFONT, R_SYN_IMG, S_SYN_IMG, SENDSIGNAL

    SPR_SYN_SEND = SendSprite()
    SENDSIGNAL = pygame.sprite.Group(SPR_SYN_SEND)

    pygame.init()
    FPSCLOCK = pygame.time.Clock()
    pygame.display.set_icon(pygame.image.load('gameicon.png'))
    DISPLAYSURF = pygame.display.set_mode((WINWIDTH, WINHEIGHT))
    pygame.display.set_caption("The Brain's Synapses")
    BASICFONT = pygame.font.Font('freesansbold.ttf', 32)

    while True:
        runGame()

def runGame():
    while True:
        DISPLAYSURF.fill(WHITE)
        event = pygame.event.poll()
        SENDSIGNAL.update()
        SENDSIGNAL.draw(DISPLAYSURF)
        pygame.display.flip()

        if winMode:
            DISPLAYSURF.blit(winSurf, winRect)
            DISPLAYSURF.blit(winSurf2, winRect2)

        pygame.display.update()
        FPSCLOCK.tick(FPS)

def terminate():
    pygame.quit()
    sys.exit()

if __name__ == '__main__':
    main()